1. Field of the Invention
The present invention relates, in general, to a full face mask that provides a sealed interface with the nose and mouth of a user, and, in particular, to a full face mask having an oral cushion portion that seals generally around the mouth and a nasal interface portion that seals generally at or around the nares and remains below the bridge of the nose.
2. Description of the Related Art
A variety of respiratory masks are known that have flexible seals, cover a portion of a user's face, and are designed to create a seal against the user's face. Because of the sealing effect that is created, gases can be provided at a positive pressure within the mask for consumption by the user. The uses for such masks range from high altitude breathing, i.e., aviation applications, to mining and fire fighting applications, to various medical diagnostic and therapeutic applications. For example, such masks are used in the delivery of continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the user's respiratory cycle or which varies with the condition of the user, to treat a medical disorder, such as sleep apnea syndrome, obstructive sleep apnea (OSA), congestive heart failure, and cheynes-stokes respiration.
A requisite of such respiratory masks is that they provide an effective seal against the user's face to prevent leakage of the gas being supplied. Commonly, in prior mask configurations, a good mask-to-face seal has been attained in many instances only with considerable discomfort to the user. This problem is most crucial because such masks are typically worn for an extended period of time. One concern in such a situation is that a user may avoid wearing an uncomfortable mask, defeating the purpose of the prescribed pressure support therapy.
A wide variety of patient interfaces are known, including nasal masks that cover only the nose, nasal canulas or prongs that fit into the nares of the user, total face masks that cover a majority of the user's face, oral-nasal or full face masks that cover the nose and mouth area, among other variations.
Traditional oral-nasal masks cover the entire nose and mouth area of the user. Due to their size and bulk, they may be less comfortable and more intrusive than other masks. Some users may resist the wearing of oral-nasal masks due to physiological reasons, such as claustrophobia or clithrophobia (fear of being enclosed). Oral-nasal mask are typically heavy and bulky, may interfere with a user's facial comfort, and may not facilitate the wearing of eyeglasses. Some oral-nasal masks may irritate a user's nose bridge, which typically is an area of thin skin, where even slight pressure can cause a blood flow constriction, and, hence, skin breakdown and/or discomfort.
It can be difficult to achieve a good seal in typical oral-nasal masks due to the large and varied area being covered. This area includes the area around the mouth, the front of the face from the ends of the mouth to the nose, and the nose itself, including the bridge. The variations in contour and size from nose to mouth are much greater than those among the nose or among the mouth alone.
Another disadvantage of conventional masks is the forehead support. Typically, forehead supports stabilize the mask system as well as providing pressure point relief. The forehead support, however, is often the source of pressure point and skin break down.